Retro-Aza-Piancatelli Rearrangement Triggered Cascade Reaction of Methyl Furylacrylates with Anilines to Access Cyclopenta[b]pyrrolidinones

Abstract

A novel aza-Piancatelli rearrangement triggered cascade reaction has been developed by utilizing methyl furylacrylates as a new type of functionalized furanoxonium ion precursor, permitting rapid and flexible construction of diverse cyclopenta­[b]­pyrrolidinone derivatives. The unprecedented and highly efficient bicyclic γ-lactam product formation is originated from an unusual retro-aza-Piancatelli rearrangement of the major cis-fused multifunctionalized cyclopentenone to the minor trans-fused one followed by a lactamization reaction.

Asymmetric Ketoalkylation/Rearrangement of Alkyenlfurans via Synergistic Photoredox/Brønsted Acid Catalysis

“…This reaction also provides straightforward access to aminocyclitol scaffolds that frequently occur as core structures in numerous biologically active molecules including peramivir (antiviral), pactamycin (antibiotic), and trehazolin (glycosidase inhibitor) . Recently, a series of elegant Lewis/Brønsted-acid-based catalytic systems have been developed to address the issues of reaction efficiency and stereocontrol. , However, despite these successes, the introduction of functional groups (such as ketone, aldehyde, ester, halogen, hydroxyl, and amino groups) at the 5-substituents of 4-aminocyclopentenones via these two-component reaction processes is still challenging due to the difficulty for the prefunctionalization of furfuryl alcohols.…”

Organocatalytic Asymmetric Synthesis of Bridged Tetrahydrobenzo[b]azepines/oxepines

“…Over the past decade the Piancatelli rearrangement initiated cascade cyclization has become a powerful platform for the construction of polycyclic molecules in organic synthesis. − In recent years, our group has been engaged in developing asymmetric variants of these reactions and related cascade/sequential processes for the enantioselective construction of diverse multifunctionalized cyclopentenones and polycyclic cyclopentanones . We successfully realized the construction of enantioenriched bridged cyclic compounds by combining this rearrangement with an intramolecular Michael addition reaction .…”

Cu(I)/Chiral Vanadium Complex Cooperatively Catalyzed Asymmetric Sulfonation/Rearrangement of Alkenylfurans

“…The prominent examples are the Nazarov cyclization and Piancatelli rearrangement, which rely on divinyl ketones and furfuryl alcohols as precursors to the requisite pentadienyl cation intermediates. Despite the elegance and versatility of existing methods, − limitations associated with the prefunctionalization of divinyl ketones and furfuryl alcohols have inspired the development of new strategies and/or precursors to access the required pentadienyl cation for the construction of multifunctionalized cyclopentenones with broad diversity and functional group compatibility …”